BY R. J. tlLLYARi). 230 



of the fourth). These may be termed the upper series of Banksian 

 cells (6). The cells formed below the pseudo-media between these 

 same sectors are four in number in each wing, and may be called 

 the lomer series of Banksian cells (b'). They lie distad from im„. 

 The Pseudo-cuhitus (Cu'). - In the forewing, this vein is formed 

 basaJly by the main stem of Cu up to cuf. It is then continued 

 by Cui, Mo, Ml, B4, Bj,, and Bo overlapping each other in turn, 

 and finally ends on Bj alone, with a small distal forking. In the 

 hindwing, the pseudo-cubitus arises from R, proximad to the 

 origin of M'. It is formed basal ly by the main stem of M as far 

 as mf, then by M2 alone, then by M., and Cuj fused for two cells' 

 length, then by M„ alone again for a cell's length, then by M2, 

 Ml, B4, B3, and Bo overlapping each other in turn, and finally 

 by B„ alone, with a distal forking as in the forewing. The cells 

 between it and the posterior wing-border may be termed the 

 posterior series of cells (p). 



We are now able to realise how exceedingly complex these 

 two apparently simple longitudinal veins really are, and how 

 impossible it would be, by any protracted studies in the com- 

 parative venation of the imagines of the family and its allies, 

 to arrive at the solution which was all the time ready to our 

 hands, for anyone who cared to take the trouble to obtain the 

 pupae in the right stage. That solution shows us, indeed, that 

 the wing-venation of the Chrysopidte is not only, as Petersen 

 suspected, " the most abnormal of all the families," but that it is 

 indeed one of the most abnormal and highly specialised vena- 

 tions to be found within the Insecta. Judged from this stand- 

 point, the (Jhrysopidcp stand far and away above all other Neu- 

 roptera in the effect and extent of their wing-specialisation. 



One point remains to be mentioned in connection with the 

 complex veins M' and Cu'. If we compare Text-fig.5 and Plate 

 xi , figs. 1-2, with the transparency overlying Plate x., we see 

 that, in order to achieve the imaginal result, the overlappiny of 

 the Banksian sectors, one upon another, needs to be much greater 

 than it is in the pupal wing. In fact, as seen in Text-fig.5, these 

 do not overlap at all, but barely meet. How can we explain 

 thisi The answer is that the overlapping is not present in the 



